The present invention is related to nonwoven composite materials. More particularly, the invention relates to a composite sheet material that is soft and absorbent on one side, and relatively abrasive on the other side. The nonwoven composite material has properties that make it suitable for use as a cleaning scrub pad and wipe.
Various types of nonwoven abrasive products have been used in the cleaning industry. For example, U.S. Pat. No. 4,227,350 discloses an abrasive product comprising a uniform lofty web of continuous three-dimensionally bonded polyamide filaments. Similarly, U.S. Pat. No. 4,078,340 discloses an abrasive pad comprising a lofty fibrous nonwoven structure of mixed denier nylon or polyester crimped fibers, which are bonded together with a binder that contains finely divided abrasive particles. These types of abrasive cleaning pads are preferably used for cleaning various surfaces, such as removing paint, grease, dirt, or other surface coatings, or preparing surfaces for painting or other coating operations.
Conventional cleaning pads such as these and others known in the art have the difficult task of providing sufficient abrasiveness to the work surface, yet cannot be damaging thereto. Certain materials can be overly abrasive to the work surface, and thus cleaning pads made from these materials have limited use. Many cleaning pads are also relatively expensive to manufacture, particularly if natural fibers are used. Manufacturing cost is further compounded if more than one type of material is used in the cleaning pad, such as in the pads mentioned above. In particular, the materials used in the cleaning pad may be difficult to attach and/or maintain together, so expensive manufacturing techniques and materials may be required. Attaching the abrasive materials to the pad can also add cost, as expensive binder resins may be required, which also add complexity to the manufacturing operation. Accordingly, there is a need for a cleaning pad, such as to be used for cleaning and wiping surfaces, that is easy and inexpensive to manufacture, yet can be used on a wide variety of work surfaces without scratching.
The present invention provides a nonwoven composite cleaning pad that comprises two nonwoven layers laminated together. According to one embodiment, the first nonwoven layer has an absorbent surface, and the second layer has a plurality of abrasive polymer formations on the exposed surface. Advantageously, the first and second layers are nonwoven materials, which are relatively inexpensive to manufacture and can be easily bonded together. In addition, the nonwoven materials are selected to provide one side that is relatively abrasive, such as for scrubbing surfaces, while the other side is soft and absorbent in order to retain water and be able to wipe up any liquid or particles after scrubbing.
More specifically, in one embodiment of the present invention one of the nonwoven layers is a nonwoven structure comprising hydrophilic staple fibers. For example, the nonwoven structure may be a carded nonwoven web formed of a blend of polypropylene fibers and rayon fibers. In one particularly advantageous embodiment, the nonwoven web is formed of about 80% polypropylene fibers and about 20% rayon fibers. The nonwoven web presents a soft absorbent surface. Regardless of the fiber composition, the fibers can be bonded to one another at discrete points according to a predetermined pattern in order to add strength to the web.
The other nonwoven layer is preferably formed of continuous filaments. More particularly, the nonwoven layer is preferably a spunbond nonwoven web formed of substantially continuous filaments. In one embodiment, the nonwoven layer comprises a polyester spunbond nonwoven web of trilobal filaments having a basis weight of at least about 2.0 oz./yd2. Advantageously, both layers comprising the cleaning pad of the present invention are nonwoven materials, which makes the cleaning pad easier to manufacture and less expensive as well.
The cleaning pad of the present invention also includes a plurality of abrasive polymer formations applied to the exposed surface of the second layer. According to one embodiment, the abrasive formations are formed of a thermoplastic polymer, such as polyester. The degree of abrasiveness can be controlled by altering the melt viscosity of the polymer composition and/or the size, spacing or shape of the polymer formations.
A method of manufacturing a nonwoven composite is also described, wherein a first nonwoven layer is provided having an absorbent surface. According to one embodiment, a second nonwoven layer is laminated to the first layer, and a plurality of abrasive polymer formations are provided on the surface of the second layer. The polymer formations are applied using a heated roll, which is preferably engraved with a predetermined pattern of indentations.
Accordingly, the cleaning pad of the present invention is easier to manufacture and maintains its integrity compared to conventional cleaning pads. Advantageously, the composite preferably comprises two web-like layers made from 100% nonwoven materials, which eases manufacturing and reduces cost. The nonwoven materials are easily adhered to one another, such as with standard lamination processes known in the art. The polymer formations on the surface of one of the layers of the cleaning pad provide a relatively abrasive surface, yet will not scratch, such that the pad can be used to clean a wide variety of surfaces, such as marble, glass, plastic, ceramic, Teflon(copyright), and the like. As such, consumers can use the composite of the present invention without fear of damaging the particular work surface. The cleaning pad of the present invention can also be used as a personal care article, such as an exfoliating scrub pad or wipe.